ABSTRACT
Background: Understanding the kinetics and longevity of antibody responses to SARS-CoV-2 is critical to informing strategies toward reducing Coronavirus disease 2019 (COVID-19) reinfections, and improving vaccination and therapy approaches. Methods: We evaluated antibody titers against SARS-CoV-2 nucleocapsid (N), spike (S), and receptor binding domain (RBD) of spike in 98 convalescent participants who experienced asymptomatic, mild, moderate or severe COVID-19 disease and in 17 non-vaccinated, non-infected controls, using four different antibody assays. Participants were sampled longitudinally at 1, 3, 6, and 12 months post-SARS-CoV-2 positive PCR test. Findings: Increasing acute COVID-19 disease severity correlated with higher anti-N and anti-RBD antibody titers throughout 12 months post-infection. Anti-N and anti-RBD titers declined over time in all participants, with the exception of increased anti-RBD titers post-vaccination, and the decay rates were faster in hospitalized compared to non-hospitalized participants. <50% of participants retained anti-N titers above control levels at 12 months, with non-hospitalized participants falling below control levels sooner. Nearly all hospitalized and non-hospitalized participants maintained anti-RBD titers above controls for up to 12 months, suggesting longevity of protection against severe reinfections. Nonetheless, by 6 months, few participants retained >50% of their 1-month anti-N or anti-RBD titers. Vaccine-induced increases in anti-RBD titers were greater in non-hospitalized relative to hospitalized participants. Early convalescent antibody titers correlated with age, but no association was observed between Post-Acute Sequelae of SARS-CoV-2 infection (PASC) status or acute steroid treatment and convalescent antibody titers. Interpretation: Hospitalized participants developed higher anti-SARS-CoV-2 antibody titers relative to non-hospitalized participants, a difference that persisted throughout 12 months, despite the faster decline in titers in hospitalized participants. In both groups, while anti-N titers fell below control levels for at least half of the participants, anti-RBD titers remained above control levels for almost all participants over 12 months, demonstrating generation of long-lived antibody responses known to correlate with protection from severe disease across COVID-19 severities. Overall, our findings contribute to the evolving understanding of COVID-19 antibody dynamics. Funding: Austin Public Health, NIAAA, Babson Diagnostics, Dell Medical School Startup.
ABSTRACT
BACKGROUND: Because data are lacking, we examined the acute effect of exercise on ambulatory blood pressure (BP) in premenopausal white women (n = 18) and black women (n = 15) with normal (n = 21) and high (n = 12) BP. METHODS: Women performed 40 minutes of control and moderate-intensity exercise. BP and hormones were measured before, during, and after the control and exercise periods. By means of RMANCOVA (repeated measures analysis of covarience), we tested whether BP and hormones differed with time and between ethnic, BP, and experimental groups. Multiple regression analysis was used to examine hormonal mediators of the postexercise BP response. RESULTS: Among white women with hypertension, average daytime systolic (S) and diastolic (D) BP decreased 11.0 +/- 3.3 mm Hg (-2.9, -19.1; P =.017) and 8.2 +/- 2.8 mm Hg (-1.2, -13.9; P =.000), from 142.6 +/- 5.8 mm Hg and 96.1 +/- 2.8 mm Hg, respectively, after exercise. Among black women with high BP, mean daytime SBP rose 12.5 +/- 5.2 mm Hg (-2.0, 27.1; P =.000) after exercise, from 121.8 +/- 6.1 mm Hg, whereas DBP was similar before and after exercise (81.4 +/- 4.3 mm Hg and 82.8 +/- 4.7 mm Hg, respectively). In white women without hypertension, daytime SBP and DBP were similar before and after exercise. In black women without hypertension, mean daytime SBP increased 6.3 +/- 2.6 mm Hg (0.4, 12.1; P =.000) after exercise from 103.6 +/- 1.4 mm Hg, and DBP did not change. In black women, hypertension (P = 0.000) and exercise-mediated insulin decreases (P =.005) explained 85.6% of the postexercise SBP response (P =.000). In white women, hypertension (P =.003) and baseline plasma renin (P =.049) accounted for 53.3% of the postexercise SBP response (P =.001). Exercise acutely reduced daytime BP in white women, but not in black women with high BP. CONCLUSION: Endurance exercise may adversely affect the BP of black women.
